The scheduled passenger flight from Dublin (EIDW) with 128 passengers, 5 crew and 4 supernumerary crew members landed normally on runway (RWY) 25 at Charleroi Airport/Brussels South (CRL) at 11.40 hrs. After landing, the First Officer, who was the pilot-flying the aircraft (PF), handed over control to the Captain somewhere prior to runway exit S2 and she elected to vacate the runway at exit S1, which is at the end of the runway. During this left turning off manoeuvre the nose wheel and right main landing gear departed the paved taxiway surface onto the soft grassy area. ATC was advised and the aircraft engines were shut down. The passengers disembarked the aircraft normally and were bussed to the terminal. The airport was then closed to traffic until 13.48 hrs when RWY 25 was declared fully operational again.